ministry officials cia they remain on alert for the possibility of another nuclear test in the north. spoke person said the north koreans have been preparing for a nuclear test at a southern tunnel in addition to the western one that was used on tuesday. kim said the entrance of the western tunnel appears to be intact after the underground explosion. he said no radioactive materials have been detected because the tunnel had containment walls to prevent an outflow of blast winds. >>> meanwhile, army commanders are preparing south korean troops in case of a military conflict they held an artillery exercise and invited the media to observe. the second artillery brigade conducted a shelling drill near the demilitarized zone. canine self-pro felled howitzers and multi-launchers fired at targets. soldiers checked their speed and accuracy. >> translator: if we face any military provocation we will strike the enemy with overwhelming firepower. we will destroy the aggressors and their supporting units. >> south korean military leaders have released video footage of recently deployed cruise missiles.